I could really go for some watermelon

I feel like my body is craving healthy food. Being extremely broke this summer has meant that my diet has been flushed down the toilet, with everything I can buy with coupons or that is on sale. This usually means food that is not good for me in anyway. Anyone have any tips for eating healthy but inexpensive?

I would love some watermelon right now, the only food I could eat none stop.